Discontinuities found in ISIMIP3a climate input data #2

Iliusi Vega del Valle opened this caveat 8 months, 1 week ago.

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Details

Title
Discontinuities found in ISIMIP3a climate input data
Description
Unfortunately, the bias-adjustment problem identified in ISIMIP3b [1] also affects the observational climate forcings provided in ISIMIP3a. There, the bias adjustment method is applied to adjust GSWP3, ensuring a smooth transition to W5E5 in the combined forcing dataset GWSP3-W5E5. For the period 1901-1978, this adjustment introduces similar jumps in the seasonal cycle as found in the bias-adjusted GCM data; see the multi-year daily mean value plots for all Giorgi regions in [2].

The same problem exists in the original GSWP3 data. As this dataset is provided externally, the ISIMIP team cannot fix it alone. Hence they are currently exploring different options of how to backward-extend the W5E5 dataset, for the case that the discontinuities in GSWP3 cannot be removed.

Therefore both the ISIMIP3b bias-adjusted climate input data, and the ISIMIP3a observational and counterfactual climate input datasets (both GSWP3-W5E5 and GSWP3) will be updated. More information on planned updates for these datasets in [3].

PLEASE DO NOT START ANY NEW ISIMIP3a SIMULATIONS.

The ISIMIP team will try to gauge the impact of the discontinuities on downstream impact variables, based on already submitted ISIMIP3a simulations, to help decide whether those simulations need to be repeated. Discussions with the sector coordinators will follow, in order to decide how to handle already completed runs.
If you have already done ISIMIP3a/3b simulations, please get in touch with the sector coordinators.

[1] https://www.isimip.org/gettingstarted/input-data-changelog/isimip3b-discontinuities-found-bias-adjusted-climate-input-data/
[2] https://www.isimip.org/files/plots/inputdata/ISIMIP3a/annual_cycle/png_united/
[3] https://www.isimip.org/gettingstarted/input-data-changelog/isimip3a-discontinuities-found-climate-input-data/
Severity
medium
Status
on hold
Versions
all versions affected
Data product
Input Data
Input category
Climate forcing
Input subcategory
Atmosphere
Climate forcing
GSWP3, GSWP3-W5E5
Climate scenario
counterclim, obsclim, spinclim
Climate variable
hurs, huss, pr, ps, rlds, rsds, sfcwind, tas, tasmax, tasmin
Simulation round
ISIMIP3a simulation round

Comments

Iliusi Vega del Valle commented 7 months, 2 weeks ago.
Updates are expected to become available soon, hopefully by mid May 2021. Stay tuned.
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Affected datasets